package edu.gyc.test;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.atomic.AtomicStampedReference;

public class ABADemo {
    static AtomicReference<Integer> atomicReference = new AtomicReference<>(100);
    static AtomicStampedReference<Integer> atomicStampedReference = new AtomicStampedReference<>(100, 1);

    public static void main(String[] args) {
        new Thread(()->{
            atomicReference.compareAndSet(100, 101);
            atomicReference.compareAndSet(101, 100);
        },"t1").start();

        new Thread(()->{
            try {
                TimeUnit.SECONDS.sleep(1);//等待一秒 保证t1线程完成ABA操作
            }catch (InterruptedException e){
               e.printStackTrace();
            }
            System.out.println(atomicReference.compareAndSet(100,2019)+"\t"+atomicReference.get());
        },"t2").start();

        try {
            TimeUnit.SECONDS.sleep(2);
        }catch (InterruptedException e){
            e.printStackTrace();
        }
        System.out.println("*********解决ABA安全问题************");

        new Thread(()->{
            int stamp=atomicStampedReference.getStamp();
            System.out.println(Thread.currentThread().getName()+"\t第一次版本号："+stamp);
            try {
                TimeUnit.SECONDS.sleep(1);
            }catch (InterruptedException e){
                e.printStackTrace();
            }
            atomicStampedReference.compareAndSet(100, 101, atomicStampedReference.getStamp(),
                    atomicStampedReference.getStamp() + 1);
            System.out.println(Thread.currentThread().getName()+"\t第二次版本号："+atomicStampedReference.getStamp());
            atomicStampedReference.compareAndSet(101, 100, atomicStampedReference.getStamp(),
                    atomicStampedReference.getStamp() + 1);
            System.out.println(Thread.currentThread().getName()+"\t第三次版本号："+atomicStampedReference.getStamp());

        },"t3").start();

        new Thread(()->{
            int stamp=atomicStampedReference.getStamp();
            System.out.println(Thread.currentThread().getName()+"\t第一次版本号："+stamp);
            try {
                TimeUnit.SECONDS.sleep(3);
            }catch (InterruptedException e){
                e.printStackTrace();
            }
         boolean result=   atomicStampedReference.compareAndSet(100, 2019, stamp, stamp + 1);
            System.out.println(Thread.currentThread().getName()+"\t修改成功否："+result+"\t当前版本号："+atomicStampedReference.getStamp());
            System.out.println(Thread.currentThread().getName()+"\t当前实际最新值："+atomicStampedReference.getReference());

            },"t4").start();

    }

}
